A cyclic process of peptide design, peptide synthesis and peptide conformation study is used to refine methods of determining oligopeptide conformation in solution and predicting it from amino acid sequence. The principal technique for conformation study is high resolution nuclear resonance, coupled with model building and empirical calculation of conformation. Correlations are made with optical (ORD, CD) data, crystallographic results, and chemical reactivity. The peptides to be used in this work will be (a) synthetic cyclic oligopeptides, (b) linear oligopeptides, designed to fold into strongly preferred conformations other than helical, (c) isotopically labeled peptides obtained by cleavage of the algal protein phycocyanin, and (d) synthetic analogs of peptide hormones. BIBLIOGRAPHIC REFERENCES: K.D. Kopple, A. Go and D.R. Pilipauskas, Studies of Peptide Conformation. Evidence for Beta-Structures in Solutions of Tetrapeptides Containing Proline, J. Amer. Chem. Soc., 97, 6830 (1975). K.D. Kopple and A. Go, Folded Conformations of Tetrapeptides in Hydrogen Bonding Solvents, in R. Walter and J. Meienhofer, eds., Peptides, Chemistry Structure and Biology, Ann Arbor Science Publishers, Ann Arbor, Mich., 1975.